CA1104483A - Seat back latch mechanism - Google Patents
Seat back latch mechanismInfo
- Publication number
- CA1104483A CA1104483A CA303,976A CA303976A CA1104483A CA 1104483 A CA1104483 A CA 1104483A CA 303976 A CA303976 A CA 303976A CA 1104483 A CA1104483 A CA 1104483A
- Authority
- CA
- Canada
- Prior art keywords
- latch
- latch pawl
- pawl
- arm
- seat
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60N—SEATS SPECIALLY ADAPTED FOR VEHICLES; VEHICLE PASSENGER ACCOMMODATION NOT OTHERWISE PROVIDED FOR
- B60N2/00—Seats specially adapted for vehicles; Arrangement or mounting of seats in vehicles
- B60N2/24—Seats specially adapted for vehicles; Arrangement or mounting of seats in vehicles for particular purposes or particular vehicles
- B60N2/42—Seats specially adapted for vehicles; Arrangement or mounting of seats in vehicles for particular purposes or particular vehicles the seat constructed to protect the occupant from the effect of abnormal g-forces, e.g. crash or safety seats
- B60N2/433—Safety locks for back-rests, e.g. with locking bars activated by inertia
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60N—SEATS SPECIALLY ADAPTED FOR VEHICLES; VEHICLE PASSENGER ACCOMMODATION NOT OTHERWISE PROVIDED FOR
- B60N2/00—Seats specially adapted for vehicles; Arrangement or mounting of seats in vehicles
- B60N2/02—Seats specially adapted for vehicles; Arrangement or mounting of seats in vehicles the seat or part thereof being movable, e.g. adjustable
- B60N2/20—Seats specially adapted for vehicles; Arrangement or mounting of seats in vehicles the seat or part thereof being movable, e.g. adjustable the back-rest being tiltable, e.g. to permit easy access
Landscapes
- Engineering & Computer Science (AREA)
- Aviation & Aerospace Engineering (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Chairs For Special Purposes, Such As Reclining Chairs (AREA)
- Seats For Vehicles (AREA)
Abstract
SEAT BACK LATCH MECHANISM
ABSTRACT OF THE DISCLOSURE
A seat back latch mechanism for a vehicle seat assembly having a generally horizontal seat structure and an upstanding backrest structure pivotally supported on support arms for tiltable movement over the seat structure.
A latch pawl pivotally mounted on one of the structures is maintained in a cam controlled latching attitude relative to a fixed detent on the other of the structures. The latch pawl is constructed and arranged so that its center of gravity normally provides a force couple acting eccen-trically of the pawl pivot axis to cause the latter to swing out of the controlled latching attitude in a direction to bypass the detent when moderate force is applied to the seat back structure to tilt the latter over the seat structure.
Upon the occurrence of a vehicular deceleration rate sufficient to overcome the inertia of the seat backrest structure which normally resists tilting movement of the latter over the seat structure, the inertia of the latch pawl becomes a factor in causing the latch pawl to engage the detent to prevent tilting movement of the backrest structure.
ABSTRACT OF THE DISCLOSURE
A seat back latch mechanism for a vehicle seat assembly having a generally horizontal seat structure and an upstanding backrest structure pivotally supported on support arms for tiltable movement over the seat structure.
A latch pawl pivotally mounted on one of the structures is maintained in a cam controlled latching attitude relative to a fixed detent on the other of the structures. The latch pawl is constructed and arranged so that its center of gravity normally provides a force couple acting eccen-trically of the pawl pivot axis to cause the latter to swing out of the controlled latching attitude in a direction to bypass the detent when moderate force is applied to the seat back structure to tilt the latter over the seat structure.
Upon the occurrence of a vehicular deceleration rate sufficient to overcome the inertia of the seat backrest structure which normally resists tilting movement of the latter over the seat structure, the inertia of the latch pawl becomes a factor in causing the latch pawl to engage the detent to prevent tilting movement of the backrest structure.
Description
~Ll~ 3 The present invention is directed to a seat back latch mechanism.
The prior art, as exemplified by U.S. Patent
The prior art, as exemplified by U.S. Patent
2,873,794, issued to J.D. Leslie et al on February 17, 1959 for an "INERTIA LATCH" and U.S. Patent 3,549,202 issued December 22, 1970 to John A. Boschen and Albert R. Close, for "SEAT BACK INERTIA LATCH", disclosed the use of inertia latch mechanisms for holding the pivoted or folding seat backrest of certain motor vehicle seat assemblies, such as those utilized in two-door models, against tiltable movement relative to the horizontal seat cushion. In such inertia latch mechanisms, the latch pawl or the like normally is positioned in a latching attitude. The inertia of the latch pawl is utilized to prevent forward tilting movement of the backrest when the deceleration rate of the vehicle exceeds a predetermined maximum, such as occurs in an accident or under "panic stop" conditions.
The latching o~ the backrest under such conditions contributes to the stability of the seat occupant and also enables the backrest to function as a protective barrier for the rear seat occupants.
When a moderate force is applied to the backrest to tilt it forwardly, the latch pawl is moveable either by gravity or spring bias to a non-latching attitude. The backrest thus may be tilted forwardly by the application o moderate manual pressure at a lo~ rate such as is desirable to permit ingress or egress to or from the rear seat area o~ the passenger compartment7 In the present inVention a latch pawl is normally biased, as by gravity, into engagement with a cam means operative to control the latching attitude of the latch , .. . _ .... .. .... .. . . .
441~33 pawl relative to a detent, the co-action between the latch pawl and the cam means causing a positive pre-positioning of the latch pawl into latching attitude and a better controlled movement of the latch pawl into and out of latching attitude than is obtainable by known inertia latch mechanisms.
The seat back latch mechanism embodying the present invention is adapted for use with a vehicle seat assembly having a substantially horizontal seat structure and an upstanding backrest pivotally supported on support arms for tiltable movement over the seat structure. The latch mechanism comprises a latch pawl having first, second and third arms mounted on the backrest structure on a pivot means permitting swinging movement about a pivot axis. The latch pawl arms extend substantially radially from the pivot axis. The latch pawl co-acts with a latch control member mounted on the seat structure, the latch control member comprising a substantially horizontally extending ramp having at one end a cam portion and terminating at its other end in a detent portion. In normal upright position of the backrest structure, an end portion of the first arm is engaged with the cam portion to maintain an end portion of the second arm in latching attitude relative to the ramp detent portion. The latch pawl third arm extends upwardly from the ~uncture of the first and second arms ; with its center of gravity offset relative to the latch pawl pivot axis to create a force couple acting eccentrically of the pivot axis to maintain engagement of the latch pawl with the cam portion as the latch pawl moves across the latch control member ramp during the application of a moderate tilting force to the backrest structure. The cam B
l~g~83 portion is contoured to rock the latching pawl in a direction to swing the second arm end portion out of latching attitude in a direction to bypass the detent portion. When a vehicle is at rest or is accelerating or decelerating at a reasonable rate, the inertia of the backrest structure normally resists tilting movement of the latter over the seat structllre. Upon the occurrence of high vehicular deceleration rate sufficient to over-come the inertia of the backrest structure normally resisting tilting movement of the latter over the seat structure, the inertia of the latch pawl becomes a factor in causing disengagement of the latch pawl first arm and portion from the ramp cam portion while maintaining the second arm end portion in its latching attitude relative to the ramp detent portion whereby the pawl is operative to prevent tilting movement of the backrest structure.
The invention is described further, by way of illustration, with reference to the accompanying drawings, wherein:
Figure 1 is a partial side view of a motor vehicle seat assembly having a generally horizontal seat structure and an upstanding backrest structure pivotally supported on support arms for tiltable movement over the seat struc-ture, and further having a latch mechanism constructed in accordance with the present invention mounted thereon;
Figures 2, 3, 4 and 5 are views in part similar to Figure 1 showing the latch mechanism in different operative positions; and Figure 5 is a section view on the line 5-5 of Figure 3.
Referring now to the drawings, and in particular to Figure 1, there is illustrated a seat back latch mechanism, 11~4~83 generally designated 10, mounted on a seat assembly 11, only one side of which is visible. The seat assembly 11 has a substantially horizontal seat structure 12 and an upstand- .
ing backrest structure 13. The backrest structure 13 is sup-ported on swingable support arms 14, only one of which is visible, each arm 14 being pivotally mounted on a - 4a -pivot pin 15 intermediate the ends of a vertically elongated lower arm 16 attached by rivets 17 or the like to a support plate secured to the frame structure 18 of the seat structure 12. Each support arm 14 is riveted or bolted by fastening devices 19 to the frame structure 21 of the backrest structure 13.
The latch mechanism 10 comprises a generally trifurcated latch pawl 22 mounted intermediate the vertical ends of the support arm 14 for swinging movement about a pivot axis provided by a pivot pin 23. As viewed in Figure 1, which represents the normal relationship of the seat - assembly components with the ~ackrest structure at rest in an upstanding position, th~ pivot pin 23 is located above and slightly to the rear of the pivot pin 15 mounting the support arm 14 on the lower arm 16. Thus, the pivot axis of the pawl 22 is located above and slig~tly to the rear of the pivot axis about which the backrest structure is swingable.
The three arms orbranches of the trifurcated pawl 22 comprise a rearwardly extending arm 24 terminating in an end portion 25, a ~orwardly extending arm 26 terminating in an end portion 27 and a substantially upstanding arm 28.
Mounted on the seat structure beneath and adjacent the latc~ pawl 22 is a latch pawl movement control mem~er 2q~ As shown in the drawings, the control member is an extension of the lo~er arm 16 and, for purposes of definition, is considered as comprising a planar body poxtion 31 of the latter extending from about the level of the pi~ot pin 15 upwardly,toward the latch pawl 22, The extension or planar body poxtion may be integral with the support arm 16 as shown or it may be a separate member -- 5 ~
. ~y~ .
' ' , .
suitably appended to the support arm 16 in any convenient manner. In either case, the planar body portion 31 sub-stantially parallels the plane of s~inging movement of the support arm 14.
At its upper edge, the control member body portion comprises a substantially horizontally-extending ramp having A cam surface 32 beginning at the rear edge 33 and extending toward the front edge 34 where it terminates in a detent portion 35. The cam surface 32 has a ramp section 36 adjacent the body portion edge 33 which blends into a curved or arcuate intermediate section 37 leading to a flat section 38.
As best seen in Figure 5, the support arm 16 comprises a single thickness of metal while the support arm 14 compri-ses two spaced plates 14a and 14b straddling the upper or planar body portion 31 of the support arm 16. The latch p~wl 22 is interposed between the plates 14a and 14b. It will be noted that the fasteners 19 securing the upper arm 14 to the backrest frame sheet metal 3~ have a spacer por-tion l9a to maintain plates 14a and 14~ in proper spaced relation to each other to permit the latch pawl 22 to swing freely therebetween.
The planar body portion 31 has an arcuate slot 41 extending radially about the pivot pin 15. A pin 42 extending between t~e plates 14a and 14b is msvable from one end of the slot 41 as the ~ackrest is tilted from a normal upstanding position as in Figure 1 to a position overlying the seat cushion as in Figure 3. The pin 42 and slot 41 provides stops limiting the movement of the back-rest in each direction of tilt.
One additional stop 43 is positioned on the upper support arm 14 to limit the swinging mo~ement of the latch pawl 22 in a counterclockwise direction as viewed in the drawings. The necessity of this top 43 will become apparent as the description proceeds.
Figures 1, 2 and 3 illustrate the following oper-ative positions of the latching mechanism 10: (1) Latching mechanism attitude when the backrest is in normal upright position; ~ latching mechanism attitude during the folding or tilting cycle of the backrest; and ~3) latching m~chanism at end of folding cycle.
Referring to Figure 1, the center of gravity, as indicated by the legend 'ICenter of Gravity", of the latching pawl 22 is ~ehind its pivot 23 and thus creates a force couple tending to swing the latching pawl in a clockwise direction. The end portion 25 of the pa~-l arm 24 engages the surface of the intermediate section 36 of the ramp cam surface 32 of the cont~ol member ~ody portion 31. In this position, the end portion 27 of the pawl arm 26 is in alignment with the detent 35 for ready engagement under predetermined deceleration of the vehicle.
When the backxest i5 rotated in a tilted direction over the horizontal seat structure 12, as ~y the application of moderate manual force when lt is desired to provide easier ingress or egress to the rear paSSengQr compartment, the ramp, in e~fect, drops away from the pawl arm and portion 25. Stated another way, the pawl pivot 23 is raised relative to the cam surface 32. The center of gravit~ of the latch pawl 22 causes the latter to rotate in a clock~ise direction as the end portion 25 attempts to follow the cam surface 32. This rotation causes the end portion 27 of the pawl arm 26 to mo~e upwardly a~ove the , detent 35, and, there~ore, out of alignment with the latter as shown in Figure 2. This movement of the pawl allows the backrest structure 13 to be tilted over the seat structure within the limits of movement permitted by the pin 42 moving within the slot 41. As this occurs, the center of gravity of the pawl 22 passes over the pawl pivot 32 causing the pawl to swing in counterclockwise direction and to assume the position shown in Figure 3. Counterclockwise movement of the pawl is limited by the engagement of the end 25 of the pawl arm 24 with the stop 43.
Figure 4 illustrates the attitude of the latching pawl 22 upon rapid deceleration of the vehicle as occurs under p~nic stop or frontal impact conditions. During rapid - deceleration of the vehicle, the backrest will start to rotate in a counterclockwise direction. Because of the location of the center of gravity of the latching pawl, a second ~orce couple is created as indicated ~y the horizontal vector. This second force couple is substantially greater than the ~orce couple normally tending to rotate the latching ~0 pawl 22 i n a clock~ise direction, see Figure 1. The second force couple rotates the locking pawl in a counter-clockwise direction causing it to remain in locking orientation, end port~on 27 in engagement with detent 35, so as to lock the backrest against tilting movement over the seat structure.
If the backrest should bounce to ~ts rest or upright position ~fter latchin~ once and then rebound into a tilted attitude, the cam sur~ace will have again pre-positioned the pawl into a latching oriePtation ready to engage the detent once again. Although vehicle decleration may have ceased by the time re~ounding takes place, the tilting motion , occurs fast enough so there is insufficient time for the pawl end portion 25 to follow the cam surface 32 and to avoid engagement of the pawl with the detent.
It will be understood that the invention is not to be limited to the exact construction shown and described, - but that various changes and modifications may be made without department from the spirit and scope of the in-vention as defined in the appended claims.
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The latching o~ the backrest under such conditions contributes to the stability of the seat occupant and also enables the backrest to function as a protective barrier for the rear seat occupants.
When a moderate force is applied to the backrest to tilt it forwardly, the latch pawl is moveable either by gravity or spring bias to a non-latching attitude. The backrest thus may be tilted forwardly by the application o moderate manual pressure at a lo~ rate such as is desirable to permit ingress or egress to or from the rear seat area o~ the passenger compartment7 In the present inVention a latch pawl is normally biased, as by gravity, into engagement with a cam means operative to control the latching attitude of the latch , .. . _ .... .. .... .. . . .
441~33 pawl relative to a detent, the co-action between the latch pawl and the cam means causing a positive pre-positioning of the latch pawl into latching attitude and a better controlled movement of the latch pawl into and out of latching attitude than is obtainable by known inertia latch mechanisms.
The seat back latch mechanism embodying the present invention is adapted for use with a vehicle seat assembly having a substantially horizontal seat structure and an upstanding backrest pivotally supported on support arms for tiltable movement over the seat structure. The latch mechanism comprises a latch pawl having first, second and third arms mounted on the backrest structure on a pivot means permitting swinging movement about a pivot axis. The latch pawl arms extend substantially radially from the pivot axis. The latch pawl co-acts with a latch control member mounted on the seat structure, the latch control member comprising a substantially horizontally extending ramp having at one end a cam portion and terminating at its other end in a detent portion. In normal upright position of the backrest structure, an end portion of the first arm is engaged with the cam portion to maintain an end portion of the second arm in latching attitude relative to the ramp detent portion. The latch pawl third arm extends upwardly from the ~uncture of the first and second arms ; with its center of gravity offset relative to the latch pawl pivot axis to create a force couple acting eccentrically of the pivot axis to maintain engagement of the latch pawl with the cam portion as the latch pawl moves across the latch control member ramp during the application of a moderate tilting force to the backrest structure. The cam B
l~g~83 portion is contoured to rock the latching pawl in a direction to swing the second arm end portion out of latching attitude in a direction to bypass the detent portion. When a vehicle is at rest or is accelerating or decelerating at a reasonable rate, the inertia of the backrest structure normally resists tilting movement of the latter over the seat structllre. Upon the occurrence of high vehicular deceleration rate sufficient to over-come the inertia of the backrest structure normally resisting tilting movement of the latter over the seat structure, the inertia of the latch pawl becomes a factor in causing disengagement of the latch pawl first arm and portion from the ramp cam portion while maintaining the second arm end portion in its latching attitude relative to the ramp detent portion whereby the pawl is operative to prevent tilting movement of the backrest structure.
The invention is described further, by way of illustration, with reference to the accompanying drawings, wherein:
Figure 1 is a partial side view of a motor vehicle seat assembly having a generally horizontal seat structure and an upstanding backrest structure pivotally supported on support arms for tiltable movement over the seat struc-ture, and further having a latch mechanism constructed in accordance with the present invention mounted thereon;
Figures 2, 3, 4 and 5 are views in part similar to Figure 1 showing the latch mechanism in different operative positions; and Figure 5 is a section view on the line 5-5 of Figure 3.
Referring now to the drawings, and in particular to Figure 1, there is illustrated a seat back latch mechanism, 11~4~83 generally designated 10, mounted on a seat assembly 11, only one side of which is visible. The seat assembly 11 has a substantially horizontal seat structure 12 and an upstand- .
ing backrest structure 13. The backrest structure 13 is sup-ported on swingable support arms 14, only one of which is visible, each arm 14 being pivotally mounted on a - 4a -pivot pin 15 intermediate the ends of a vertically elongated lower arm 16 attached by rivets 17 or the like to a support plate secured to the frame structure 18 of the seat structure 12. Each support arm 14 is riveted or bolted by fastening devices 19 to the frame structure 21 of the backrest structure 13.
The latch mechanism 10 comprises a generally trifurcated latch pawl 22 mounted intermediate the vertical ends of the support arm 14 for swinging movement about a pivot axis provided by a pivot pin 23. As viewed in Figure 1, which represents the normal relationship of the seat - assembly components with the ~ackrest structure at rest in an upstanding position, th~ pivot pin 23 is located above and slightly to the rear of the pivot pin 15 mounting the support arm 14 on the lower arm 16. Thus, the pivot axis of the pawl 22 is located above and slig~tly to the rear of the pivot axis about which the backrest structure is swingable.
The three arms orbranches of the trifurcated pawl 22 comprise a rearwardly extending arm 24 terminating in an end portion 25, a ~orwardly extending arm 26 terminating in an end portion 27 and a substantially upstanding arm 28.
Mounted on the seat structure beneath and adjacent the latc~ pawl 22 is a latch pawl movement control mem~er 2q~ As shown in the drawings, the control member is an extension of the lo~er arm 16 and, for purposes of definition, is considered as comprising a planar body poxtion 31 of the latter extending from about the level of the pi~ot pin 15 upwardly,toward the latch pawl 22, The extension or planar body poxtion may be integral with the support arm 16 as shown or it may be a separate member -- 5 ~
. ~y~ .
' ' , .
suitably appended to the support arm 16 in any convenient manner. In either case, the planar body portion 31 sub-stantially parallels the plane of s~inging movement of the support arm 14.
At its upper edge, the control member body portion comprises a substantially horizontally-extending ramp having A cam surface 32 beginning at the rear edge 33 and extending toward the front edge 34 where it terminates in a detent portion 35. The cam surface 32 has a ramp section 36 adjacent the body portion edge 33 which blends into a curved or arcuate intermediate section 37 leading to a flat section 38.
As best seen in Figure 5, the support arm 16 comprises a single thickness of metal while the support arm 14 compri-ses two spaced plates 14a and 14b straddling the upper or planar body portion 31 of the support arm 16. The latch p~wl 22 is interposed between the plates 14a and 14b. It will be noted that the fasteners 19 securing the upper arm 14 to the backrest frame sheet metal 3~ have a spacer por-tion l9a to maintain plates 14a and 14~ in proper spaced relation to each other to permit the latch pawl 22 to swing freely therebetween.
The planar body portion 31 has an arcuate slot 41 extending radially about the pivot pin 15. A pin 42 extending between t~e plates 14a and 14b is msvable from one end of the slot 41 as the ~ackrest is tilted from a normal upstanding position as in Figure 1 to a position overlying the seat cushion as in Figure 3. The pin 42 and slot 41 provides stops limiting the movement of the back-rest in each direction of tilt.
One additional stop 43 is positioned on the upper support arm 14 to limit the swinging mo~ement of the latch pawl 22 in a counterclockwise direction as viewed in the drawings. The necessity of this top 43 will become apparent as the description proceeds.
Figures 1, 2 and 3 illustrate the following oper-ative positions of the latching mechanism 10: (1) Latching mechanism attitude when the backrest is in normal upright position; ~ latching mechanism attitude during the folding or tilting cycle of the backrest; and ~3) latching m~chanism at end of folding cycle.
Referring to Figure 1, the center of gravity, as indicated by the legend 'ICenter of Gravity", of the latching pawl 22 is ~ehind its pivot 23 and thus creates a force couple tending to swing the latching pawl in a clockwise direction. The end portion 25 of the pa~-l arm 24 engages the surface of the intermediate section 36 of the ramp cam surface 32 of the cont~ol member ~ody portion 31. In this position, the end portion 27 of the pawl arm 26 is in alignment with the detent 35 for ready engagement under predetermined deceleration of the vehicle.
When the backxest i5 rotated in a tilted direction over the horizontal seat structure 12, as ~y the application of moderate manual force when lt is desired to provide easier ingress or egress to the rear paSSengQr compartment, the ramp, in e~fect, drops away from the pawl arm and portion 25. Stated another way, the pawl pivot 23 is raised relative to the cam surface 32. The center of gravit~ of the latch pawl 22 causes the latter to rotate in a clock~ise direction as the end portion 25 attempts to follow the cam surface 32. This rotation causes the end portion 27 of the pawl arm 26 to mo~e upwardly a~ove the , detent 35, and, there~ore, out of alignment with the latter as shown in Figure 2. This movement of the pawl allows the backrest structure 13 to be tilted over the seat structure within the limits of movement permitted by the pin 42 moving within the slot 41. As this occurs, the center of gravity of the pawl 22 passes over the pawl pivot 32 causing the pawl to swing in counterclockwise direction and to assume the position shown in Figure 3. Counterclockwise movement of the pawl is limited by the engagement of the end 25 of the pawl arm 24 with the stop 43.
Figure 4 illustrates the attitude of the latching pawl 22 upon rapid deceleration of the vehicle as occurs under p~nic stop or frontal impact conditions. During rapid - deceleration of the vehicle, the backrest will start to rotate in a counterclockwise direction. Because of the location of the center of gravity of the latching pawl, a second ~orce couple is created as indicated ~y the horizontal vector. This second force couple is substantially greater than the ~orce couple normally tending to rotate the latching ~0 pawl 22 i n a clock~ise direction, see Figure 1. The second force couple rotates the locking pawl in a counter-clockwise direction causing it to remain in locking orientation, end port~on 27 in engagement with detent 35, so as to lock the backrest against tilting movement over the seat structure.
If the backrest should bounce to ~ts rest or upright position ~fter latchin~ once and then rebound into a tilted attitude, the cam sur~ace will have again pre-positioned the pawl into a latching oriePtation ready to engage the detent once again. Although vehicle decleration may have ceased by the time re~ounding takes place, the tilting motion , occurs fast enough so there is insufficient time for the pawl end portion 25 to follow the cam surface 32 and to avoid engagement of the pawl with the detent.
It will be understood that the invention is not to be limited to the exact construction shown and described, - but that various changes and modifications may be made without department from the spirit and scope of the in-vention as defined in the appended claims.
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Claims (3)
1. A seat back latch mechanism for a vehicle seat assembly having a substantially horizontal seat structure and an upstanding backrest structure pivotally supported on support arms for tiltable movement over the seat structure, the latch mechanism comprising:
a latch pawl having first, second and third arms, pivot means on the backrest structure mounting the latch pawl on one of the structures for swinging movement about a pivot axis, the latch pawl arms extending substantially radially from the pivot axis, and a latch control member mounted on the seat structure, the latch control member comprising a substantially horizontally extending ramp having at one end a cam portion and terminating at its other end in a detent portion, in normal upright position of the backrest struc-ture an end portion of the first arm being engaged with the cam portion to maintain an end portion of the second arm in latching attitude relative to the ramp detent portion, the latch pawl third arm extending upwardly from the juncture of the first and second arms with its center of gravity offset relative to the latch pawl pivot axis to create a force couple acting eccentrically of the pivot axis to maintain engagement of the latch pawl with the cam portion as the latch pawl moves across the latch control member ramp during the application of a moderate tilting force to the backrest structure, the cam portion being contoured to rock the latch pawl in a direction to swing the second arm end portion out of latching attitude in a direction to bypass the detent portion, and upon the occurrence of a high vehicular deceler-ation rate sufficient to overcome the inertia of the back-rest structure normally resisting tilting movement of the latter over the seat structure, the inertia of the latch pawl becoming a factor in causing disengagement of the latch pawl first arm end portion from the ramp cam portion while maintaining the second arm end portion in its latching atti-tude relative to the ramp detent portion whereby the pawl is operative to prevent tilting movement of the backrest structure.
- 10a -
a latch pawl having first, second and third arms, pivot means on the backrest structure mounting the latch pawl on one of the structures for swinging movement about a pivot axis, the latch pawl arms extending substantially radially from the pivot axis, and a latch control member mounted on the seat structure, the latch control member comprising a substantially horizontally extending ramp having at one end a cam portion and terminating at its other end in a detent portion, in normal upright position of the backrest struc-ture an end portion of the first arm being engaged with the cam portion to maintain an end portion of the second arm in latching attitude relative to the ramp detent portion, the latch pawl third arm extending upwardly from the juncture of the first and second arms with its center of gravity offset relative to the latch pawl pivot axis to create a force couple acting eccentrically of the pivot axis to maintain engagement of the latch pawl with the cam portion as the latch pawl moves across the latch control member ramp during the application of a moderate tilting force to the backrest structure, the cam portion being contoured to rock the latch pawl in a direction to swing the second arm end portion out of latching attitude in a direction to bypass the detent portion, and upon the occurrence of a high vehicular deceler-ation rate sufficient to overcome the inertia of the back-rest structure normally resisting tilting movement of the latter over the seat structure, the inertia of the latch pawl becoming a factor in causing disengagement of the latch pawl first arm end portion from the ramp cam portion while maintaining the second arm end portion in its latching atti-tude relative to the ramp detent portion whereby the pawl is operative to prevent tilting movement of the backrest structure.
- 10a -
2. A seat back latch mechanism for a vehicle seat assembly having a substantially horizontal seat structure and an upstanding backrest structure supported on swingable support arms pivotally mounted on the seat structure for tiltable movement over the latter, the latch mechanism comprising:
a latch pawl pivotally mounted on one of the support arms for swinging movement about a pivot axis located above the pivotal mounting of the support arms, the latch pawl comprising a trifurcated member having first, second and third arms arranged in a substantially inverted Y-shape configuration with the pivot axis being lo-caked at substantially the conjunction of the three arms, a latch pawl movement control member mounted on the seat structure beneath and adjacent the latch pawl and having a substantially planar body portion paralleling the plane of swinging movement of the one support arm carrying the latch pawl, the control member having a substantially horizontal ramp on its upper edge having a cam portion beginning at one edge of the planar body portion and terminating at the other edge in a detent portion, in normal upright position of the backrest struc-ture an end portion of the first arm being engaged with the cam portion to maintain an end portion of the second arm in latching attitude relative to the ramp detent portion, the latch pawl third arm extending upwardly from the juncture of the first and second arms with its center of gravity offset relative to the latch pawl pivot axis to create a force couple acting in a direction eccentrically of the pivot axis to maintain engagement of the latch pawl with the cam portion as the latch pawl moves across the latch control member ramp during the application of moderate tilting force to the backrest structure, the cam portion being contoured to rock the latch pawl in a direction to swing out of latching attitude rela-tive to the detent portion during moderate tilting of the backrest structure, and upon the occurrence of a high vehicular dece-leration rate sufficient to overcome the inertia of the back-rest structure normally resisting tilting movement of the latter over the seat structure, a force couple being created which is greater than and acts in a direction opposite to the direction of the first mentioned force couple to cause the latch pawl first arm end portion to be lifted from the cam portion while maintaining the latch pawl second arm portion in latching attitude whereby the latter is operative to engage the detent portion to prevent tilting movement of the backrest structure.
a latch pawl pivotally mounted on one of the support arms for swinging movement about a pivot axis located above the pivotal mounting of the support arms, the latch pawl comprising a trifurcated member having first, second and third arms arranged in a substantially inverted Y-shape configuration with the pivot axis being lo-caked at substantially the conjunction of the three arms, a latch pawl movement control member mounted on the seat structure beneath and adjacent the latch pawl and having a substantially planar body portion paralleling the plane of swinging movement of the one support arm carrying the latch pawl, the control member having a substantially horizontal ramp on its upper edge having a cam portion beginning at one edge of the planar body portion and terminating at the other edge in a detent portion, in normal upright position of the backrest struc-ture an end portion of the first arm being engaged with the cam portion to maintain an end portion of the second arm in latching attitude relative to the ramp detent portion, the latch pawl third arm extending upwardly from the juncture of the first and second arms with its center of gravity offset relative to the latch pawl pivot axis to create a force couple acting in a direction eccentrically of the pivot axis to maintain engagement of the latch pawl with the cam portion as the latch pawl moves across the latch control member ramp during the application of moderate tilting force to the backrest structure, the cam portion being contoured to rock the latch pawl in a direction to swing out of latching attitude rela-tive to the detent portion during moderate tilting of the backrest structure, and upon the occurrence of a high vehicular dece-leration rate sufficient to overcome the inertia of the back-rest structure normally resisting tilting movement of the latter over the seat structure, a force couple being created which is greater than and acts in a direction opposite to the direction of the first mentioned force couple to cause the latch pawl first arm end portion to be lifted from the cam portion while maintaining the latch pawl second arm portion in latching attitude whereby the latter is operative to engage the detent portion to prevent tilting movement of the backrest structure.
3. A seat back latch mechanism for a vehicle seat assembly having a substantially horizontal seat structure and an upstanding backrest structure pivotally supported on support arms for tiltable movement over the seat structure, the latch mechanism comprising:
a latch pawl having first, second and third arms, pivot means on the backrest structure mounting the latch pawl for swinging movement about a pivot axis, the latch pawl arms extending substantially radi-ally from the pivot axis, and a latch control member mounted on the seat structure, the latch control member comprising a substantially horizontally extending ramp having at one end a cam portion and terminating at its other end in a detent portion, in normal upright position of the backrest structure an end portion of the first arm being engaged with the cam portion to maintain an end portion of the second arm in latching attitude relative to the ramp detent portion, the latch pawl third arm extending upwardly from the juncture of the first and second arms with its center of gravity offset relative to the latch pawl pivot axis to create a force couple acting eccentrically of the pivot axis to maintain engagement of the latch pawl with the cam portion as the latch pawl moves across the latch control member ramp during the application of a moderate tilting force to the backrest structure, the cam portion being contoured to rock the latch pawl in a direction to swing the second arm end portion out of latching attitude in a direction to bypass the detent portion, upon occurrence of a high vehicular deceleration rate the normal at rest inertia of the latch pawl is overcome creating a force couple greater than and acting opposite to the first mentioned force couple to swing the latch pawl in a direction so that the first arm end portion is lifted from the cam portion and the second arm end portion is maintained in latching attitude as the backrest structure tries to tilt over the seat structure, thereby abruptly terminating any tilting movement upon engagement of the second arm end portion with the ramp detent portion.
a latch pawl having first, second and third arms, pivot means on the backrest structure mounting the latch pawl for swinging movement about a pivot axis, the latch pawl arms extending substantially radi-ally from the pivot axis, and a latch control member mounted on the seat structure, the latch control member comprising a substantially horizontally extending ramp having at one end a cam portion and terminating at its other end in a detent portion, in normal upright position of the backrest structure an end portion of the first arm being engaged with the cam portion to maintain an end portion of the second arm in latching attitude relative to the ramp detent portion, the latch pawl third arm extending upwardly from the juncture of the first and second arms with its center of gravity offset relative to the latch pawl pivot axis to create a force couple acting eccentrically of the pivot axis to maintain engagement of the latch pawl with the cam portion as the latch pawl moves across the latch control member ramp during the application of a moderate tilting force to the backrest structure, the cam portion being contoured to rock the latch pawl in a direction to swing the second arm end portion out of latching attitude in a direction to bypass the detent portion, upon occurrence of a high vehicular deceleration rate the normal at rest inertia of the latch pawl is overcome creating a force couple greater than and acting opposite to the first mentioned force couple to swing the latch pawl in a direction so that the first arm end portion is lifted from the cam portion and the second arm end portion is maintained in latching attitude as the backrest structure tries to tilt over the seat structure, thereby abruptly terminating any tilting movement upon engagement of the second arm end portion with the ramp detent portion.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/819,920 US4318569A (en) | 1977-07-28 | 1977-07-28 | Seat back latch mechanism |
| US819,920 | 1977-07-28 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1104483A true CA1104483A (en) | 1981-07-07 |
Family
ID=25229442
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA303,976A Expired CA1104483A (en) | 1977-07-28 | 1978-05-24 | Seat back latch mechanism |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US4318569A (en) |
| CA (1) | CA1104483A (en) |
Families Citing this family (30)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2641587C2 (en) * | 1976-09-16 | 1983-12-01 | Keiper Automobiltechnik Gmbh & Co Kg, 5630 Remscheid | Articulated fittings for seats, in particular motor vehicle seats |
| USRE32884E (en) * | 1979-11-01 | 1989-03-07 | Keiper Recaro Incorporated | Superfine tooth seat back adjuster |
| DE3046888A1 (en) * | 1980-12-12 | 1982-07-15 | Keiper Automobiltechnik Gmbh & Co Kg, 5630 Remscheid | JOINT FITTING FOR SEATS, IN PARTICULAR MOTOR VEHICLE SEATS |
| US4365837A (en) * | 1981-03-05 | 1982-12-28 | Hoover Universal, Inc. | Inertial lock |
| US4390208A (en) * | 1981-04-27 | 1983-06-28 | General Motors Corporation | Inertia responsive seat back latching mechanism |
| US4438974A (en) * | 1981-09-24 | 1984-03-27 | Keiper U.S.A., Inc. | Guide profile for inertia latch |
| FR2556946B1 (en) * | 1983-10-25 | 1986-12-12 | Sable | MOBILE SEAT, IN PARTICULAR REMOVABLE SEAT FOR VEHICLE |
| CA1232527A (en) * | 1985-10-25 | 1988-02-09 | Martyn Hiscox | Inertial latching mechanism for seat assemblies |
| US4733912A (en) * | 1986-10-30 | 1988-03-29 | Fisher Dynamics Corporation | Inertia sensitive seat hinge mechanism |
| CA1242135A (en) * | 1986-10-31 | 1988-09-20 | Magna International Inc. | One-piece pawl |
| US4919482A (en) * | 1987-01-20 | 1990-04-24 | Lear Siegler Seating Corp. | Inertia latch for vehicle seats |
| US4756577A (en) * | 1987-04-13 | 1988-07-12 | General Motors Corporation | Lock mechanism for a car seat back and recliner |
| US5100202A (en) * | 1989-05-24 | 1992-03-31 | Canadian A.S.E. Limited | Low-chuck inertial latching mechanism for seat assemblies |
| US5163736A (en) * | 1991-05-21 | 1992-11-17 | Ford Motor Company | Inertial lock mechanism for vehicle seat reclining apparatus |
| US5265937A (en) * | 1992-06-29 | 1993-11-30 | General Motors Corporation | Seat back inertia lock |
| US5370440A (en) * | 1992-07-27 | 1994-12-06 | Lear Seating Corporation | Inertia responsive latching mechanism for seat assemblies |
| CA2089203C (en) * | 1993-02-10 | 1998-02-17 | Gulam Premji | Zero chuck vehicle seat latching mechanism |
| US5460429A (en) * | 1994-01-31 | 1995-10-24 | Fisher Dynamics Corporation | Inertia latch assembly for seat hinge mechanism |
| US5476307A (en) * | 1994-01-31 | 1995-12-19 | Fisher Dynamics Corporation | Inertia hinge for seatback and armrest |
| EP1181937A3 (en) * | 1994-08-09 | 2004-02-04 | Cytrx Corporation | Novel vaccine adjuvant and vaccine |
| US5626391A (en) * | 1995-05-25 | 1997-05-06 | Bertrand Faure Ltd. | Uptiltable rear vehicle seat assembly |
| US5658043A (en) * | 1995-12-28 | 1997-08-19 | Lear Corporation | Inertia lock for side-mounted armrest |
| US6048027A (en) * | 1996-04-16 | 2000-04-11 | Lear Corporation | Vehicle seat with integral child restraint seat |
| FR2857305B1 (en) * | 2003-07-10 | 2005-10-07 | Faurecia Sieges Automobile | ARTICULATED BACKHOE VEHICLE SEAT COMPRISING MEANS FOR BLOCKING THE BACKREST IN THE EVENT OF A FRONTAL SHOCK |
| FR2874199B1 (en) * | 2004-08-11 | 2008-05-16 | Faurecia Sieges Automobile | VEHICLE SEAT WITH SECURITY DEVICE |
| WO2011040903A1 (en) * | 2009-09-29 | 2011-04-07 | Lear Corporation | Seat assembly having a soft latch mechanism |
| DE102014111923B4 (en) * | 2014-08-20 | 2017-03-30 | Volkswagen Aktiengesellschaft | Armrest with crash protection |
| US9758070B1 (en) | 2016-06-10 | 2017-09-12 | Ford Global Technologies, Llc | Second row flip up cushion inertia hook |
| US10315540B2 (en) | 2016-12-06 | 2019-06-11 | Ford Global Technologies, Llc | Inertia stop link for stadium style seat cushion stowed positioning |
| DE102018110525A1 (en) * | 2018-05-02 | 2019-11-07 | Faurecia Autositze Gmbh | Method for mounting a transmission component of a seat height adjustment |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2873794A (en) * | 1956-09-24 | 1959-02-17 | Gen Motors Corp | Inertia latch |
| US3398987A (en) * | 1966-12-01 | 1968-08-27 | Young Spring & Wire Corp | Folding automobile seat |
| US3549202A (en) * | 1969-05-01 | 1970-12-22 | Ford Motor Co | Seat back inertia latch |
| US3674309A (en) * | 1970-10-30 | 1972-07-04 | Gen Motors Corp | Vehicle seat latch |
| DE2306312C3 (en) * | 1973-02-09 | 1979-12-06 | Keiper Automobiltechnik Gmbh & Co Kg, 5630 Remscheid | Hinged fitting for vehicle seats with a safety lock |
-
1977
- 1977-07-28 US US05/819,920 patent/US4318569A/en not_active Expired - Lifetime
-
1978
- 1978-05-24 CA CA303,976A patent/CA1104483A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| US4318569A (en) | 1982-03-09 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |